I have a solar-powered Steve's cart managing an automatic wheat farm and I want to use all the extra wheat and seeds that come out as bio-fuel with IC2. However, in order to make bio-fuel I need to stick the plant-balls into tin cells, which get consumed/destroyed when I put the fuel into a can using a canning machine, so the system will need to have tin continually supplied, which will keep it from being fully self-sustaining. It would be WONDERFUL if I could get the empty cells back to recycle them. I thought of perhaps using some of the power produced by burning the fuel in a generator to make some UU-M to make more tin, but it turns out (unsurprisingly) that the energy required to make the necessary amount of tin (148,600 EU) is greater than the amount I get from burning the fuel in a generator (104,160). XD